After months of arduous negotiations between competing promoters and rival champions, the contract for a two-fight deal between Tyson Fury and Anthony Joshua to unify the heavyweight titles has been finally signed.

"We'd like to get a site deal confirmed in the next month," said Eddie Hearn, managing director of Matchroom Sport, Joshua's promoter. "The hard part is always getting everybody to put pen to paper. But this was a major effort from all parties to get this over the line. You had rival promoters, rival networks and rival fighters."

Not to mention, rival egos, always a factor in boxing. The final signature came Saturday, in a Provision of Services agreement whose signees are believed to include Fury and Joshua; Joshua's promoter, Matchroom Boxing; Fury's American promoter, Top Rank; Fury's English promoter, Queensbury; and Fury's management company, Dubai-based MTK.

With the terms of the deal now agreed, principals can solicit offers from prospective sites.

"I actually feel we've done the hard part," said Hearn. "Speaking for myself, Anthony and his team at 258 management, I know how hard we've worked hard these last couple of months and I just feel that this fight is so big it's not a difficult sell. We've already had approaches from eight or nine sites. The offers have come from multiple countries in the Middle East, from Asia, eastern Europe and America."

The smart money, however, continues to be on the Middle East, where Hearn secured a site fee in excess of $40 million to promote Joshua's 2019 rematch with Andy Ruiz in Saudi Arabia. The need for a huge site fee becomes particularly acute with seating restrictions and businesses still reeling from COVID, as middle eastern countries are seeking less in attendance than favorable publicity.

"This is the biggest fight in boxing and one of the biggest sporting events in the world," Hearn said. "It will be a major, major win for a country that wants to showcase itself."

As ESPN previously reported, the contract calls for a 50-50 split in the first fight and 60-40 in the rematch, with the winner taking the higher share. The plan is for both fights to take place in 2021 -- the first in June or July, the rematch ideally taking place in November or December. But news of the deal comes just days after Fury expressed frustration with the negotiations that began back in January, telling IFL-TV that he had ceased training for Joshua and was drinking "up to 12 pints a day."

"You never really know with Tyson," said Hearn. "It could be mind games. He could be having a bad day. He could be a little pissed off. Or he could be having a joke.

"One of the fascinations about this fight will be the build-up because they're two totally different characters, two totally different personalities," Hearn said. "The mind games will be on another level for this fight. Tyson is very good at that. Anthony is excited by that...He's so pumped, so focused, he hasn't stopped training since the [Kubrat] Pulev fight [in December]. He's like a caged lion. The buildup is going to be epic."